When a study proposes to include people who can communicate but cannot provide their own consent, the IRB will typically require some sort of assent process or document be used to explain the proposed research to the subject. This requirement is most often seen in studies involving minor children age 7 and up.
Please keep the reading level of the target population in mind when drafting assent materials. We’ve seen some assent forms that read as high as a 9th-grade level, when the age range of eligibility dips down into the 1st- and 2nd-grade range. Simple language and formatting that will be familiar to the very young (e.g. lots of white space, graphics as appropriate) will make it easier for kids to understand what they’re being asked to do. And keep in mind that if your subject population spans a large age range, such as 7 to 17 years old, you may want to create more than one version of assent materials, with each targeted to a different age group.